Take good care of the eight passes, don't be afraid to raise crayfish!

Crayfish is a kind of creature with strong vitality, which has taken root everywhere in just a few years after it was introduced into our country. now crayfish has become the protagonist of the night market and has a good breeding prospect, so how can we raise crayfish well? Take good care of the eight passes, don't be afraid to raise crayfish!

First, close the planting of aquatic plants.

Resurrected aquatic plants should be planted in shrimp ponds, mainly submerged plants (Elorella verticillata, verticillium verticillata, bitter grass, etc.), supplemented by floating plants (hollow cabbage, duckweed, etc.), properly matched with some water plants (Artemisia, Reed, etc.). Plant Elodea verticillata in shallow slopes, verticillium verticillata, bitter grass, hollow cabbage, duckweed in deep water, and Reed and Zizania caduciflora in shoals. The coverage rate of aquatic plants should reach 50%. If it is too thin, it should be replenished in time, and if it is too dense, it should be cut manually.

Second, release and restocking of good seedlings

Free-range crayfish seedlings should be of neat specifications, strong physique, strong vitality, intact appendages, no injury or disease. The specification of shrimp fry should reach 0.8 cm, the specification of crayfish species should be more than 3 cm, the stocking density should be reasonable, and the specification of stocking in the same pond should be the same. Crayfish seedlings need to be bathed in 3%-4% salt water for 5 minutes for 10 minutes before stocking to kill pathogenic bacteria and parasites. In order to make full use of the culture water space, increase the culture yield and improve the culture efficiency, some silver carp species can be stocked with 100g ∕ tail and 100g ∕ mu. Stocking silver carp species in culture ponds can also play a role in purifying water quality.

Third, put the good feed into and off

Crayfish belong to omnivorous shrimp, especially like to eat animal bait, and the nature of greed, food intake. Therefore, the nutrition of the feed should be comprehensive and the feeding amount should be moderate. If the feeding amount is insufficient, it will affect the growth and even cause mutual killing; if the feeding amount is too large, it will cause feed waste and pollute the water quality; if the feed nutrition is not comprehensive, it will cause malnutrition, cause molting failure and affect growth.

In high-density culture, crayfish are mainly fed with compound feed. When shrimp seedlings and shrimp species first enter the pond, a large number of rotifers, cladocera, copepods and aquatic insect larvae can be fed by fertilizing and topdressing. The protein content of formula feed for young shrimp should be more than 30%, and that for adult shrimp should be more than 26%. It should be fed twice a day, once in the morning and once in the evening, before sunrise in the morning and after sunset in the evening, mainly in the evening, accounting for 70% of the daily feed. The daily feeding amount is mainly determined by the total weight of crayfish in storage ponds. From March to April and after October, the daily feeding amount is 1% of the total weight of crayfish. May to October is the normal growth season of crayfish, and the daily feeding amount is about 5% of the total weight of shrimp. It should be fed more when the weather is fine, and less when it is hot and sultry, continuous rainy weather or when the water quality is too thick. A large number of shrimps are fed less when molting and more after molting. Feeding should adhere to the "four fixed" principle, namely: positioning, quantitative, timing, quality. The amount of feeding with rest should be flexibly controlled according to the weather, water temperature, water color and the growth of crayfish, and it is appropriate to eat, finish and leave no residual bait.

Fourth, keep a good control of water quality

Maintaining good water quality is beneficial to the healthy growth of crayfish. Add fresh water once every 7 to 10 days, add 20 cm of water each time to keep the water quality fresh and clean; use quicklime to disinfect the water body once every 10 to 15 days, the dosage is 10 kg ∕ mu, the method is to sprinkle the whole pool while the hydration slurry is hot, and adjust the pH value between 7.5 and 8.5 to keep the water quality weakly alkaline. Regularly use microbial preparations such as EM Water diversion King and sediment improver to reduce ammonia nitrogen, nitrite and hydrogen sulfide and other harmful substances in the pond, improve water quality and bottom quality, and control the transparency of pond water in 30cm to 40cm; usually, oxygen enrichment equipment should be turned on frequently to keep the dissolved oxygen in pond water above 5 mg ∕ liter.

5. do a good job in molting management

The larval metamorphosis, foot regeneration and growth of crayfish are always accompanied by molting. Crayfish can only grow after shedding their hard shell. Therefore, the shelling period is the critical moment for the growth of crayfish, and it is particularly important to do a good job of management during the shelling period. We should mainly do the following three points: first, we should regulate and control the water quality and keep the water quality fresh. Second, adequate feeding and comprehensive nutrition. Third, to maintain good water plants, excessive should be manually cut, deficiency should be replenished in time.

Sixth, do a good job in disease prevention and control

The prevention and control of crayfish disease should adhere to the policy of "disease prevention first, treatment as a supplement, prevention without disease and early treatment of disease". Technical measures such as strict disinfection of ponds, release of high-quality seedlings, creation of a good ecological environment, fresh feed and regular bait can effectively prevent the occurrence of shrimp disease. Once crayfish get sick, fish drugs with high efficiency, low toxicity and little side effects allowed by the state should be used for early treatment.

7. Take good control of the enemy's invasion

The main enemies of crayfish are water rats, frogs, waterbirds and some ferocious carnivorous fish. These animals can prey on crayfish and timely measures should be taken to eliminate them. For carnivorous fish, in the process of entering the water, they can be filtered through a dense net to keep them away from the mouth of the culture pond. Rat traps and cages can be used to hunt and kill rodents; for birds, some colored strips and scarecrows can be set up by the pool to drive away. The most effective way for frogs is to catch them manually at night.

8. Do a good job of timely fishing

After raising crayfish for about 2 months, the size of crayfish can reach more than 50 grams. At this time, we can start fishing and put large-sized shrimp on the market to reduce the density of crayfish in the pond and promote the rapid growth of small-sized shrimp. Fishing tools include shrimp cages, ground cages and so on.